| ELVES, like sprites,
are high-altitude manifestations of the electrical fields created by exceptionally
intense conventional lightning. They show themselves as glowing, pancake-shaped
layers (see
illustration: Electromagnetic Pulses). Elves can occur with sprites
but form first and do not last as long. The sequence of video images (below)
shows the relative timing: just before the conventional lightning strike
occurs, the sky is uniformly dark (A). The ensuing flash illuminates the
cloud deck and immediately spawns the flattened glow of elves high in the
mesosphere (B). Momentarily, sprites erupt throughout this part of the
atmosphere, adding their radiance to the faint light from the luminous
layer (C). Finally, only the sprites persist (D). |
